Optical system and projection image display device

Abstract

An optical system includes a lens array element including a transmission surface and a first reflecting surface, the transmission surface including a lens array, the first reflecting surface facing the transmission surface, the lens array element being configured to reflect, at the first reflecting surface, light received from the transmission surface and emit the light from the transmission surface; an image display element configured to convert the received light into image light and emit the image light; a plurality of optical elements configured to guide the light emitted from the lens array element to the image display element in a first order; and an opening through which the image light converted at the image display element is emitted. The plurality of optical elements guides the image light emitted from the image display element to the opening in a second order reverse to the first order.

What is claimed is: 
     
         1 . An optical system comprising:
 a lens array element including a transmission surface and a first reflecting surface, the transmission surface including a lens array, the first reflecting surface facing the transmission surface, the lens array element being configured to reflect, at the first reflecting surface, light received from the transmission surface and emit the light from the transmission surface;   an image display element configured to convert the received light into image light and emit the image light;   a plurality of optical elements configured to guide the light emitted from the lens array element to the image display element in a first order; and   an opening through which the image light converted at the image display element is emitted,   wherein the plurality of optical elements guides the image light emitted from the image display element to the opening in a second order reverse to the first order.   
     
     
         2 . The optical system according to  claim 1 , wherein the lens array element and the opening are optically conjugate to each other by the plurality of optical elements. 
     
     
         3 . The optical system according to  claim 2 , wherein the plurality of optical elements includes a split surface where light is split,
 wherein the split surface is configured to reflect first polarized light and transmit second polarized light, and   wherein the lens array element is configured to receive and reflect the light in a first polarization state reflected from the split surface or the light in a second polarization state transmitted through the split surface.   
     
     
         4 . The optical system according to  claim 3 , further comprising at least one retardation plate configured to change a polarization state of the light. 
     
     
         5 . The optical system according to  claim 4 , wherein the at least one retardation plate is a ¼ wave plate. 
     
     
         6 . The optical system according to  claim 4 , wherein the plurality of optical elements includes a second reflecting surface from which the light reflected at the lens array element and received via the split surface is reflected, and
 wherein the at least one retardation plate includes   a first retardation plate disposed between the lens array element and the split surface, and   a second retardation plate disposed between the split surface and the second reflecting surface.   
     
     
         7 . The optical system according to  claim 6 , further comprising a light source that emits light,
 wherein the split surface allows light in the first polarization state out of the light emitted from the light source to be reflect and guided to the lens array element through the first retardation plate,   wherein the lens array element allows the light to be reflected and guided to the split surface through the first retardation plate,   wherein the first retardation plate allows the light to pass through in a reciprocating manner, and allows the polarization state of the light to be changed from the first polarization state to the second polarization state,   wherein the split surface allows the light brought into the second polarization state at the first retardation plate to be transmitted through the split surface and guided to the second reflecting surface through the second retardation plate,   wherein the second reflecting surface allows the light to be reflected and guided to the split surface through the second retardation plate,   wherein the second retardation plate allows the light to pass through in a reciprocating manner, and allows the polarization state of the light to be changed from the second polarization state to the first polarization state,   wherein the split surface allows the light brought into the first polarization state at the second retardation plate to be reflected and guided to the image display element,   wherein the image display element allows the light to be converted into the image light and allows the image light to be guided to the split surface,   wherein the split surface allows the image light to be reflected and guided to the second reflecting surface through the second retardation plate,   wherein the second reflecting surface allows the image light to be reflected and guided to the split surface through the second retardation plate,   wherein the second retardation plate allows the image light to pass through in a reciprocating manner, and allows a polarization state of the image light to be changed from the first polarization state to the second polarization state, and   wherein the split surface allows the image light brought into the second polarization state at the second retardation plate to be transmitted through the split surface and guided to the opening.   
     
     
         8 . The optical system according to  claim 6 , further comprising a light source that emits light,
 wherein the split surface allows light in a second polarization state out of the light emitted from the light source to be transmitted through the split surface and guided to the lens array element through the first retardation plate,   wherein the lens array element allows the light to be reflected and guided to the split surface through the first retardation plate,   wherein the first retardation plate allows the light to pass through in a reciprocating manner, and allows the polarization state of the light to be changed from the second polarization state to the first polarization state,   wherein the split surface allows the light brought into the first polarization state at the first retardation plate to be reflected and guided to the second reflecting surface through the second retardation plate,   wherein the second reflecting surface allows the light to be reflected and guided to the split surface through the second retardation plate,   wherein the second retardation plate allows the light to pass through in a reciprocating manner, and allows the polarization state of the light to be changed from the first polarization state to the second polarization state,   wherein the split surface allows the light brought into the second polarization state at the second retardation plate to be transmitted through the split surface and guided to the image display element,   wherein the image display element allows the light to be converted into the image light and allows the image light to be guided to the split surface,   wherein the split surface allows the image light to be transmitted through the split surface and guided to the second reflecting surface through the second retardation plate,   wherein the second reflecting surface allows the image light to be reflected and guided to the split surface through the second retardation plate,   wherein the second retardation plate allows the image light to pass through in a reciprocating manner, and allows the polarization state of the image light to be changed from the second polarization state to the first polarization state, and   wherein the split surface allows the image light brought into the first polarization state at the second retardation plate to be reflected and guided to the opening.   
     
     
         9 . The optical system according to  claim 3 , wherein the plurality of optical elements includes a polarization beam splitter surrounding the split surface,
 wherein the polarization beam splitter includes an outgoing surface that allows the light to be emitted via the split surface and allows the image light to be emitted, and   wherein the lens array element and the opening are disposed on a conjugate surface provided on an outgoing surface side of the polarization beam splitter.   
     
     
         10 . The optical system according to  claim 2 , wherein the plurality of optical elements each includes at least one lens element. 
     
     
         11 . The optical system according to  claim 10 , further comprising:
 a light source that emits light; and   a polarization beam splitter including a split surface that allows the light from the light source to be split,   wherein the plurality of optical elements each includes a second reflecting surface that allows the light reflected at the lens array element and received via the split surface to be reflected,   wherein the image display element allows the light reflected from the second reflecting surface and received via the split surface to be changed into image light, and   wherein the lens element includes at least one of   a first lens element disposed between the split surface and the lens array element,   a second lens element disposed between the split surface and the second reflecting surface, and   a third lens element disposed between the split surface and the image display element.   
     
     
         12 . The optical system according to  claim 11 , wherein the second reflecting surface is formed on an optical surface of the second lens element. 
     
     
         13 . The optical system according to  claim 12 , wherein the at least one lens element includes the first lens element, the second lens element, and the third lens element. 
     
     
         14 . The optical system according to  claim 3 , further comprising:
 a light source that emits light; and   a first polarizer disposed between the split surface and the light source.   
     
     
         15 . The optical system according to  claim 3 , further comprising a second polarizer disposed between the split surface and the opening. 
     
     
         16 . An optical system comprising:
 a first optical system that emits first light and second light;   a second optical system that receives the first light emitted from the first optical system; and   a third optical system that receives the second light emitted from the first optical system,   wherein the first optical system includes   a light source that collimates randomly polarized light and emits the randomly polarized light,   a polarization beam splitter including a split surface that allows the randomly polarized light to be split into first light in a first polarization state and second light in a second polarization state, the first light being obtained by reflecting first polarized light out of the randomly polarized light, the second light being obtained by transmitting second polarized light out of the randomly polarized light,   a reflector element including a second reflecting surface that allows the second light split at the split surface to be reflected, and   at least one retardation plate disposed between the polarization beam splitter and the reflector element,   wherein the split surface allows the first light to be guided to the second optical system,   wherein the at least one retardation plate allows the second light in the second polarization state to be brought into the first polarization state,   wherein the split surface allows the second light brought into the first polarization state to be reflected and guided to the third optical system,   wherein the second optical system and the third optical system each include   a lens array element that includes a transmission surface including a lens array and a reflecting surface facing the transmission surface, reflects light received from the transmission surface from the reflecting surface, and emits the light from the transmission surface,   an image display element that allows the received light to be converted into image light and emitted,   a plurality of optical elements that allows the light emitted from the lens array element to be guided to the image display element in a first order, and   an opening through which the image light converted at the image display element is emitted, and   wherein the plurality of optical elements guides the image light emitted from the image display element to the opening in a second order reverse to the first order.   
     
     
         17 . A projection image display device comprising the optical system according to  claim 1 . 
     
     
         18 . A head mount display comprising the optical system according to  claim 16 ,
 wherein the second optical system projects an image for a right eye of a user, and   wherein the third optical system projects an image for a left eye of the user.